Caffeine in Tea vs. Coffee: A Complete Comparison

Wondering why black tea can feel “smoother” than coffee and how much caffeine you’re actually getting? This guide breaks down the caffeine in tea vs coffee with clear numbers, simple tables, and evidence‑backed tips on why tea can feel steadier and how to time your intake to protect sleep.

At‑a‑glance: caffeine in tea vs. coffee

• 8 oz brewed coffee averages ~96 mg caffeine; brewed black tea ~48 mg; brewed green tea ~29 mg (Mayo Clinic caffeine chart).
• Tea may feel steadier thanks to L‑theanine, which can complement caffeine for focused attention (2010 clinical trial on L‑theanine + caffeine).
• Caffeine peaks ~15–120 minutes after drinking; average half‑life ~5 hours (range ~1.5–9.5) (NIH pharmacology review).
• Most healthy adults do well staying under ~400 mg/day (FDA consumer guidance).

How much caffeine is in coffee vs. tea?

Caffeine varies by plant, brand, and preparation. Treat these as useful averages.

Source: Mayo Clinic caffeine content guide.

What changes the numbers?

• Brew strength & time: Longer steeps and hotter water generally extract more caffeine from tea; more grounds and hotter water raise coffee’s caffeine per cup (see this overview on how brewing and steeping affect caffeine levels).
• Serving size: A 12–16 oz coffee can easily double the caffeine of the 8 oz values shown above.
• Product variability: Ready‑to‑drink teas and coffees vary; check labels when available.

Why tea’s energy can feel different

Tea leaves naturally contain L‑theanine, an amino acid linked to smoother focus. In a randomized, placebo‑controlled trial, a combination of 97 mg L‑theanine + 40 mg caffeine improved accuracy on demanding attention tasks and reduced tiredness versus a placebo. Two practical reasons tea often feels calmer:

• Lower dose per serving: Many teas land around ~20–50 mg per 8 oz vs ~80–100+ mg for a standard coffee (Mayo Clinic table).
• The L‑theanine effect: The presence of L‑theanine in tea may “smooth” the stimulant effect when taken together with caffeine in meaningful amounts.

Energy curve and timing to protect sleep

• Absorption: Peak blood levels typically occur within 15–120 minutes of drinking caffeine (NIH pharmacology review).
• Duration: Average half‑life is ~5 hours, but can range 1.5–9.5 hours based on factors like genetics, medications, smoking, and pregnancy (NIH pharmacology review).
• Practical takeaway: Many people feel better with a caffeine cutoff at least 6–8 hours before bedtime. If sleep is a struggle, move your last cup earlier and consider swapping to decaf or herbal tea.

Does roast level or tea type matter?

• Coffee roast: Roast level doesn’t significantly change caffeine per cup. Dark roast beans are less dense, so a scoop contains less coffee by weight than a scoop of light roast, resulting in slightly less caffeine. Measuring by weight (grams), not scoops, gives more consistent results.
• Tea varieties & matcha: Black, oolong, green, and white teas all come from Camellia sinensis; steep time and temperature are the biggest levers you control—longer/hotter steeps extract more caffeine. Matcha uses powdered leaf, so it can deliver more caffeine than typical steeped green tea depending on how much you use.

Choosing your drink by goal

• Smooth, sustained focus with less jitter risk: Start with black or green tea. If you use coffee, try smaller, split doses and pair with food. Some people also pair coffee with L‑theanine supplements—discuss any new supplement with your clinician first.
• Maximum alertness per cup: Brewed coffee or espresso‑based drinks deliver more caffeine per serving on average (Mayo Clinic data).
• Afternoon pick‑me‑up without sabotaging sleep: Choose green or decaf tea, or limit coffee to the morning given caffeine’s ~5‑hour half-life (NIH pharmacology review).
• Sensitive stomach or blood pressure: Tea’s lower dose per cup may be more comfortable. Be cautious with energy drinks, which can contain very high levels of caffeine and other stimulants (FDA guidance).

Safety basics and daily limits

• For most healthy adults, up to ~400 mg/day is a commonly cited upper limit; count all sources (coffee, tea, energy drinks, soda, chocolate, some meds) (FDA guidelines).
• Decaf isn’t zero: decaf coffee can still contain ~1–12 mg per 8 oz (Mayo Clinic caffeine content guide).
• For habitual users, coffee and tea contribute to daily fluid intake, as explained in our guide to Caffeine and Hydration: Does Coffee Dehydrate You?.
• If you are watching your blood pressure, see our safe intake guidelines for caffeine and blood pressure.
• Special populations: Children/teens, pregnancy/breastfeeding, certain heart or anxiety conditions, and some medications warrant lower limits or avoidance—speak with your clinician.

FAQs

Is herbal tea caffeine‑free?
Most herbal infusions (e.g., chamomile, peppermint, rooibos) are naturally caffeine‑free. However, some caffeinated herbal infusions—such as yerba mate and guayusa—are made from different plants and do contain caffeine.

Does cold brew have more caffeine?
Cold brew often uses more grounds and longer extraction, which can raise caffeine per serving compared with some hot methods. Actual content varies by recipe and brand.

Is matcha stronger than regular green tea?
Often, yes. Because you consume the powdered leaf, matcha can deliver more caffeine than steeped green tea depending on the amount used.

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The BodySpec take: Use caffeine to support—not sabotage—your goals

Used thoughtfully, both coffee and tea can boost focus and performance. To connect your caffeine habits to measurable outcomes:

• Try a 2‑week timing test: Shift all caffeine before noon and track sleep + workouts; compare to your baseline.
• Standardize on scan days: Keep caffeine, fluids, and meals consistent so lean‑mass trends are apples‑to‑apples.
• Cycle intensity: Use tea on lighter‑stim days to improve sleep quality. Better recovery supports muscle gain and fat loss—changes you can monitor with periodic DEXA scans.

Want objective feedback while you dial in daily habits? Learn how a BodySpec DEXA scan works and see how smarter sleep, training, and nutrition—caffeine timing included—change your body composition over time. Book your scan.